1. Field
The following description relates to a binder composition for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same.
2. Description of the Related Art
A rechargeable lithium battery includes positive and negative electrodes (each including a material that can reversibly intercalate/deintercalate lithium ions as the respective positive and negative active materials) and an organic electrolyte solution or a polymer electrolyte solution infused (charged) between the positive and negative electrodes. Herein, the positive and negative electrodes intercalate and deintercalate lithium ions and produce electrical energy through oxidation and reduction reactions.
As for a positive active material for a lithium rechargeable battery, a lithium-transition metal oxide capable of intercalating lithium (such as LiCoO2, LiMn2O4, LiNi1-xCoxO2 (0<x<1), or the like) has been used (i.e., utilized). As for a negative active material for a lithium rechargeable battery, various carbon-based materials (such as artificial graphite, natural graphite, or hard carbon) capable of intercalating and deintercalating lithium ions have been used. Recently, the demand for a battery having high energy density increasingly has required a negative active material having high theoretical capacity density.
Accordingly, Si, Sn, and Ge alloyed with lithium, an oxide thereof, and an alloy thereof have drawn attention as possible materials for a negative active material. In particular, a Si-based negative active material has very high charge capacity and is widely applied to a high-capacity battery. However, the Si-based negative active material may be about 300% to about 400% expanded during the charge and discharge cycles. Therefore, there is a need for a binder capable of controlling the expansion of the Si-based negative active material effectively.